Multiple string centralizer



Oct. 29, 1963 o. w. BROOKS y 3,108,639

v Y MULTIPLE STRING CENTRALIZER Filed Mayzo. 1960 Y 2 sheets-sheet 1Ora/7 l/V. 5/0 OJ INVENTOR.

4 WMM@ 3,108,639 MULTIPLE "SG CENTRALIZER Gran W. Brooks, Harris County,Tex. Filed May 2), 1960, Ser'. No. 30,572 4 Claims. (or. 16s- 241) Thepresent invention relates to anew and improved centralizer for multipletubular members and more particularly to a dual string tubingcentralizer.

In the completion or" an oil well it is often desired or necessary torun a dual string or a multiple string of tubing in the Well hole. Thetwo strings or multiple strings of tubing must be properly spaced orcentralized in the hole and in relation to each other. In endeavoring=to centralize and space multiple tubing strings in prior art operationsa large number of single tubing centralizers have been spaced along eachof the individual strings of tubing in the hole. In effect an attempt ismade to centralize each string of tubing individually. It can easily beseen that for a dual string of tubing, twice as many centralizers `arerequired and for a triple string three times as many centralizers and adinfinitum. This is not only expensive but soon becomes impractical asthe centralizer on one string must be staggered in relation to those onanother string. Further, even after positioning such a great number ofthe single tubing centralizers, such centralizers are not xed inrelation to the tubing strings themselves.

The device of the present invention overcomes the above problems in thata single centralizer is used to position or centralize all the stringsof tubing at any one depth both in relation to the well hole and inrelation to each other.

t is therefore an important object of the present invention to provide anew and improved centralizer for multiple tubular members whichpositions or centralizes a plurality of strings of tubular members inrelation to la well hole and further positions or centralizes eachstring of tubular members in relation to each other string of tubularmembers. v

Another object of the present invention is to provide a new and improvedcentralizer for multiple strings of tubing which can be quickly andeasily installed on all strings of tubing at the well head prior topositioning the tubing strings in the well hole.

Still another `object of the present invention is to provide a new andimproved centralizer for multiple strings of tubing whi-ch can beinstalled at any desired position along the tubing strings.

A further object of the present invention is to provide a new andimproved centralizer for multiple strings of tubing which can bemanufactured and sold at a relatively small amount more than the cost ofa single tubing centralizer. y

The construction designed to carry out the invention will be hereinafterdescribed, together with other features thereof.

The invention will be more readily understood from a reading yof thefollowing specification and by reference to the accompanying drawingsforming a part thereof, wherein an example of the invention is shown,and where- FIG. 1 is a side elevation illustrating one embodiment of theinvention in position on a dual string of tubing in a well hole;

FIG. 2 is a view similar to FIG. l, but rotated ninety degrees; 1

PIG. 3 is a plan view of the device of the present invention illustratedin locked position on a dual string of tubing in a well hole;

FIG. 4 is a plan View of the device of the present fie invention andillustrates the device in open position just prior to positioning thedevice on a dual tubing string;

FIG. 5 is a view similar to that of FIG. 1 but illustrates an alternateembodiment of the present invention;

FIG. 6 is a plan view of the alternate embodiment of fFiG. 5 of thepresent invention,v illustrating the device in a locked position;

lFIG. 7 is a plan view similar to that of FIG. 6, but illustrating thealternate embodiment of the present invention in an open position; and

FIG. 8 is a detailed View of the locking means used on the alternateembodiment of the present invention.

Referring now to the drawings and more particularly to FIGS. 1 4, thedevice of the present invention C is illustrated as being adapted foruse on a dual string of tuibing T positioned in a well casing W. Thedevice C includes principally an upper body 1t) and a lower body 11which are joined together by a plurality of flexible longitudinal bowsprings 112 and 13, or the like. The upper body 10 and the lower body 11are substantially alike and are each comprised of a plurality of arcuatesegments 16 and 17 which are connected together and adapted to bepositioned on the tubular string T, all of which will be described indetail hereinafter.

The curvature of each of the segments 16 and 17 is such that thesegments 16 and 17 may be positioned on the tubing T as more clearlyseen in FIG. 3. In the dual string embodiment C of FIGS. 1 4, one pair19` of the members 16 and 17 is hingedly connected together at ZtlI byany suitable means such as a pin hinge 21. The lother pair 22 of thearcuate segments 16 and 17 is releasably hinged together by a pin hinge23 similar to that of the pin hinge l2.1. Each pair of arcuate segments19 and 22 are substantially alike and in fact the members 16 and 17 ofeach of such pairs `19 and 22 can be cast from the same respectivemolds. The length of each of the segments 16 and 17 is less thanone-half of the circumference of the tubing members 25 in the tubingstring T which permits the segments 1o and .17 to be quickly and easilypositioned around the tubular members 2S and in substantial continuouscontact therewith. The members `16 are preferably shorter than themembers `1'7 thereby allowing the members 13 to be positioned directlyopposite each other for the most effective centralizmg.

The members 16 `and 17 in each of the bodies 1li and l11 are rigidlyconnected together by a short flat rectangular member 27 by welding orany other suitable means. The connection members 27 are of such lengththat when the segments 16 and 17 are positioned on the tubular members=25 of the tubing string T that the members 27 are diametrically opposedto each other. The longitudinal members `13 are welded or othenwisesuitably attached to the members 27 of the upper body 10 and thecorresponding lower body 11. The members 12 and 13` are shaped so thattheir outer portions 12' and 13 will contact the inner surface 28 Iofthe casing W and simultaneously hold the tubing string T in the desiredposition. The members 121 and 13` are preferably arranged on the bodies10 and 11 so as to be 90 from each `of the other members 12 and 13, andwith the members 12 being opposed to each other and with the members 13opposed to each other. This arrangement provides the maximum stabilitywith a minimum of members. It should be understood however, thatvariations in the arrangement and members of such longitudinal members12 and 13 can be made without departing from the scope of the invention.Suitable openings (not seen) are provided inthe member 27 for receivinga bolt 29 or the like on which a nut Sti may be placed thereon. The useof the bolt 29 and the nut 30 in each of the bodies 10 and 11 inhibitslongitudinal movement of the device C on the tubing string T.

The device of the present invention provides a centralizer C which canbe quickly and easily positioned in place on a multiple tubing stringand nmly positions the tubing string T within the casing W and alsopositions each of the tubular members 25 in relationship to each other.AS the size of the casing usually `determines the total amount of spacewithin the casing vavailable `for tubing, such space is somewhat limitedas a rule, for economical and other reasons. Normally there is notsuicient space within the casing W to position the tubular members 25 ofthe tubing strings T so that their joints Aare adjacent each other.Therefore such tubular members 25 must `be placed suiciently close toeach other so that the joints must by necessity be staggered within thecasing. This is normally done by using different lengths of tubularmembers 25 or by merely inserting a pup joint in one 4of the tubingstrings comprising the dual string of tubing T. As a result the bodiesand 11 must therefore be postioned on the tubing string on -a smootharea (i.e., one on which there are no joints).

Even utilizing the bolt 29 and nut 3G on each of the bodies 10 and 11,the centralizer C may tend to move flonygitudinally on the tubingstrings T and to eliminate :this undesirable happening, stop collars 35similar to the upper bodies 10 and the lower bodies 11 except that anadditional bolt 29 and nut 30 is provided for more positive locking ofsuch stop collars 35 on the tubing string T, may be used. Two such stopcollars 35 are illustrated in the drawings in position on the tubularmembers 25, fand it is recommended that two such stop collars 35 be usedto more positively assure that no longitudinal movement of thecentralizer C will occur. It should be noted, however that one or nostop collars can be used if desired.

The centralizer C is normally installed on the dual string T at the wellhead where it may be quickly and easily positioned on such tubingstring. FIG. 4 best illustrates the device C in an opened position justprior to positionin-g on the tubing string T. One pair 19 of arcuatemembers 16 and 17 is positioned on one tubular member of the tubularstring T and the other pair 22 of the mem-bers 16 and 17 is positionedon the other tubular member 25 of the tubing string T so that the hinges23 of each of the members 16 and 17 are brought together. A pin 20 isthen inserted in each of the hinges 23 thereby closing the bodies 10 and11 respectively on the tubular members 25. Bolts 29 are then insertedthrough the openings in the members 27 and the nuts 30 are thentightened on the bolts 29 in the usual manner thereby locking thecentralizer C on the tubing string T. This procedure is followednormally on the upper body 10 first and then on the lower body 11.Either body 10 or 11 may be positioned first las desired. As previouslystated above, stop collars are positioned as desired and can be placedon the tubing string either before or after the tubing cent-ralizer Chas been positioned on the tubing string T, but it is generallypreferred that they be placed on the tubing string T prior topositioning the device C.

FIGS. 5-8 of the drawings illustrate an 'alternate embodiment or anotherform of the invention C which is adapted to 4be positioned on a triplestring of tubing T'. The device C is similar lto the device C exceptthat it is adapted to be postioned on a triple string of tubing T andtherefore requires two additional arcuate segments 116 and 117 yand twoladditional longitudinal members or bow springs 112 and 113. The deviceC includes principally an upper body 110 and a lower body 111 with suchupper body 110 positioned directly above the lower body 111 and thebodies 110 and 111 being joined together by a plurality of longitudinalmembers 112 and 113. Each of the longitudinal members or bow springs 112and 113 are positioned on the bodies 110 and 111 in such manner that amember 112 is diam'etrioally opposed to a member 113 and such members112 and 113 are in equal numbers. The mem bers 112 and 113 are iieXedoutwardly so that their outer portions 112 and 113 will engage theinterior 4surface 128 of the casing W. The members 112 and 113 may besecured to the bodies 119 and 111 by welding or any other suitablemeans. The members 112 and 113 are pre-shaped on the basis of the sizeof the tubing members 125 in the tubing string T and the relativeposition within the casing W in which it is desired to position `suchtriple string of tubing T.

Each of the bodies and 111 are substantially alike and include yaplurality of pairs of arcuate segments 119 and 122. The arcuate segments116 and 117 comprising the pairs 119 are hingedly connected together at120 by means of a pin 121. The segments 116 and 117 cornprising the pair122 is releasably hinged together at 123. Such hinge 123 is similar tothe hinge 120 and utilizes a pin (not shown) similar to pin 121.

Each of the pairs of arcuate segments 119 and 122 are rigidly connectedto the next successive pair of arcuate members either 119 or 122 bymeans of a relatively short rectangular member 127. Each of the members127 is of a size determined by the desired relationship of theindividual tubing members 125 to each of the other tubular members 125in the triple string of tubing T. Each of the members 127 has an opening(not seen) therein adapted to receive a curved bolt 129 or the likewhich is threaded on each end and adapted to lreceive a nut 130 on eachend thereof. The position `of the bolt 129 in locked position on thetubing T' is best illustrated in FIG. 6. As such bolt 129 only extendsthrough two of the members 127, it is recommended that the bolt 129 beinserted through one different member 127 in each upper body 110 1andeach lower body 111 thereby assuring a more positive holding or lockingof the centralizer C on the tubing string T.

Stop collars constructed similarly to the bodies 110 Aand 111 exceptthat each stop collar 135 is adapted to receive at least two bolts 129`for fa more positive locking action are used to inhibit longitudinalmovement of the device C on the tubing string T'. As in the case of thestop collars 35 it is also recommended that two stop collars 135 be usedwith each centralizer C; however, one or none can be used if desired.

The installation and use of the device C is similar to that of thedevice C, and it is believed that no further description of such isnecessary.

The device C provides a multiple string tubing centralizer which notonly positions the tubing string T within the casing W' in relation tosuch casing W but also each of the members 125 comprising the tubularstring T are positioned in relation to each other. It should also benoted that the outer portions 112 and 113 of the members 112 and 113`are positioned on the bodies 110 and 111 so that the `full surface areaof such outer portion 112' and 113 is in contact with the inner surface128 of the casing W'. rIlhis assures la more positive centralizingaction and as each of the members 112 has a member 113 diametricallyopposed to it `the centralizer C is firmly positioned within the casingW.

As -additional strings of tubing are added to a multiple tubing string,additional pairs of arcuate segments similar to 16, 17 or 116, 117 maybe added to bodies similar t0 10, 11 and 110, 111 whereby the tubingcentralizer may be adapted to lit on any number of tubing members asdesired. It should also be noted that more or less longitudinal memberssimilar to 12, 13, 112 and 113 may be secured to upper and lower bodiessuch as 10, 11 and 110, 111 as desired depending upon the size of thetubular members and the number used, or as desired.

It can therefore be appreciated that the device of the present inventionprovides a multiple string ntralizer which may be quickly and easilypositioned on a multiple string of tubular members, which may be lirmlylocked in position so as to eliminate longitudinal movement arl andwhich not only positions the tubing string `within the well hole orcasing, but-also firmly positions the individual tubing members inrelationship to each other.

yIt should also be noted that the particular arrangement of thelongitudinal members such as the members 12, l13, 112 and 113 whilebeing preferred as illustrated in the drawings and described hereinabovemay be varied on the bodies 10, 11, 116 and 111 as desired withoutdeparting from the scope of the invention. Such arrangement assures amaximum stability with a minimum of longitudinal members. For similarreasons it is also recommended that the number of longitudinal memberssuch as 12 and 13 or -112 and 113 correspond to the number of arcuatesegments d6 and 17 or 116 and 117, and that two arcuate segments such as16, 17, 116 and 117 be utilized in each upper and lower body `10, 11,y110 or 1-11 Ifor each tubular member 25 and 125 within the tubingstring.

The foregoing disclosure and `description of the invention isillustrative and explanatory thereof and various changes in the size,shape and materials, as well as in the details of the illustratedconstruction, may be made Within the scope of the appended claimswithout departing ffrom the spirit of the invention.

What is claimed is:

yl. A well centralize-r for positioning multiple strings of tubularmembers in a well bore comprising an upper body and a lower body, aplurality of flexible longitudinal members attached to said upper andsaid lower bodies whereby said upper and said lower bodies are connectedto each other with said upper body being positioned directly above saidlower body, said longitudinal members forming bow springs for engagingthe well bore wall and thereby positioning said upper and said lowerbodies in a predetermined position in a well bore, each of said upperand Ilower bodies including a plurality of pairs of arcuate portions-for positioning on strings of tubular members, said pairs of arcuateportions having an arcuate length less than the circumference of thetubular member on which they are positioned, means hingedly connectingsaid pairs forming said upper body together, and means hingedlyconnecting said pairs fonming said lower body together.

2. A well centralizer for positioning multiple strings of tubularmembers in a well bore comprising an upper body and a lower body, aplurality of flexible longitudinal members attached to said upper andsaid lower bodies whereby said upper and said lower bodies are connectedto each other with said upper body being positioned Idirectly above saidlower body, said longitudinal members forming bow springs for engagingthe well bore wall and thereby positioning said upper and said lowerbodies in a predetermined position in a well bore, each of said upperand lower bodies including a plurality of pairs of arcuate portions forpositioning on strings of tubular members, means hingedly connectingsaid pairs forming said upper body together, and means hingedlyconnecting said pairs forming said lower body together, said arcuateportions in each of said pairs of arcuate portions being of an arcuatelength which is less than one-half of the circumference of one of thetubular members on which said well centralizer is to be positioned.

3. A well centralizer for positioning multiple strings of tubularmembers in a well bore comprising an upper body and a lower body, aplurality of flexible longitudinal members attached to said upper andsaid lower bodies whereby said upper and said lower bodies are connectedto each other with said upper body being positioned directly above saidlower body, said longitudinal members forming bow springs kfor engagingthe well bore wall and thereby positioning said upper and said lowerbodies in a predetermined position in a well bore, each of said upperand lower bodies including a plurality of pairs of arcuate portions forpositioning on strings of tubular members, means hingedly connectingsaid pairs lform-ing said upper body together, and means hingedlyconnecting said pairs forming said lower body together, said arcuateportions in each of said pairs of arcuate port-ions being of an arcuatelength which is less than one-half of the circumference of one of thetubular members on lwhich said well centralizer is to be positioned, oneof said arcuate portions in each of said pairs of arcuate portions beingshorter in circumferential extent than the other of said arcuateportions in said same pair of arcuate portions.

4. A well centralizer for positioning multiple strings of tubularmembers in a well bore comprising an upper body and a lower body, aplurality of ilexible longitudinal members attached to said upper andsaid lower bodies whereby said upper and -said lower bodies areconnected to each other with said upper body being positioned directlyabove said lower body, said longitudinal members forming bow springs forengaging the well bore wall and thereby positionng said upper and saidlower bodies in a predetermined position in a well bore, each of saidupper and lower bodies including a plurality of pairs of arcuateportions for positioning on strings of tubular members, means hingedlyconnecting said pairs forming said upper body together, and meanshingedly connecting said pairs `forming said lower body together, one ofsaid arcuate portions in each of said pairs of arcuate portions beingshorter in circumferential extent than the other of said arcuateportions in said same pair of arcuate portions.

Guirl Sept. 29, '1942 Baker June 2, 1953

1. A WELL CENTRALIZER FOR POSITIONING MULTIPLE STRINGS OF TUBULARMEMBERS IN A WELL BORE COMPRISING AN UPPER BODY AND A LOWER BODY, APLURALITY OF FLEXIBLE LONGITUDINAL MEMBERS ATTACHED TO SAID UPPER ANDSAID LOWER BODIES WHEREBY SAID UPPER AND SAID LOWER BODIES ARE CONNECTEDTO EACH OTHER WITH SAID UPPER BODY BEING POSITIONED DIRECTLY ABOVE SAIDLOWER BODY, A SAID LONGITUDINAL MEMBERS FORMING BOW SPRINGS FOR ENGAGINGTHE WELL BORE WALL AND THEREBY POSITIONING SAID UPPER AND SAID LOWERBODIES IN A PREDERERMINED POSITION IN A WELL BORE, EACH OF SAID UPPERAND LOWER BODIES INCLUDING A PLURALITY OF PAIRS OF ARCUATE PORTIONS FORPOSITIONING ON STRINGS OF TUBULAR MEMBERS, SAID PAIRS OF ARCUATEPORTIONS HAVING AN ARCUATE LENGTH LESS THAN THE CIRCUMFERENCE OF THETUBULAR MEMBER ON WHICH THEY ARE POSITINED, MEANS HINGEDLY CONNECTINGSAID PAIRS FORMING SAID UPPER BODY TOGETHER, AND MEANS HINGEDLYCONNECTING SAID PAIRS FORMING SAID LOWER BODY TOGETHER.